Embed Size (px)
Citation preview
Louisiana State UniversityLSU Digital Commons
LSU Master's Theses Graduate School
2012
The impact of 5S on the safety climate ofmanufacturing workersSiddarth SrinivasanLouisiana State University and Agricultural and Mechanical College
Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_theses
Part of the Construction Engineering and Management Commons
This Thesis is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSUMaster's Theses by an authorized graduate school editor of LSU Digital Commons. For more information, please contact [email protected].
Recommended CitationSrinivasan, Siddarth, "The impact of 5S on the safety climate of manufacturing workers" (2012). LSU Master's Theses. 396.https://digitalcommons.lsu.edu/gradschool_theses/396
THE IMPACT OF 5S ON THE SAFETY CLIMATE OF
MANUFACTURING WORKERS
A Thesis
Submitted to the Graduate Faculty of the
Louisiana State University and Agricultural and Mechanical College
in partial fulfillment of the requirements for the degree of
Master of Science
in
Industrial Engineering
by
Siddarth Srinivasan
B. E., Anna University, 2010 December 2012
ii
To my parents
iii
ACKNOWLEDGEMENTS
Thank you, Dr. Laura Ikuma, for your continuous support and guidance throughout my
graduate program. You have been a source of inspiration for me.
Thank you, Dr. Isabelina Nahmens, for letting me work with you on different projects and
for providing valuable suggestions for my research.
Thank you, Dr. Craig Harvey, for your advice and motivation.
iv
TABLE OF CONTENTS
ACKNOWLEDGEMENTS ............................................................................................ iii LIST OF TABLES .......................................................................................................... vi
LIST OF FIGURES ....................................................................................................... vii
ABSTRACT ................................................................................................................. viii
1 INTRODUCTION .................................................................................................... 1
1.1 Motivation ............................................................................................................... 1
1.2 Improving manufacturing challenges and safety through lean .................................... 2
1.3 Objective .................................................................................................................. 3 1.4 Research scope and limitations ................................................................................. 4
2 LITERATURE REVIEW .......................................................................................... 5
2.1 Lean manufacturing ................................................................................................. 5
2.2 5S in manufacturing ................................................................................................. 6
2.3 Safety climate ......................................................................................................... 10 2.4 Safety climate in manufacturing .............................................................................. 11
2.5 Safety & lean .......................................................................................................... 13
3 METHODS ............................................................................................................. 16
3.1 Purpose of research ................................................................................................ 16
3.2 Research question and hypotheses .......................................................................... 16
3.3 Participants ............................................................................................................ 18 3.4 Safety climate survey .............................................................................................. 18
3.5 5S productivity measures ........................................................................................ 19
3.6 5S implementation ................................................................................................. 21
3.7 Experimental design ............................................................................................... 23
3.7.1 Dependent variables ...................................................................................... 23 3.7.2 Independent variables ................................................................................... 24
3.8 Procedure ............................................................................................................... 24 3.9 Statistical analysis .................................................................................................. 25
4 RESULTS ............................................................................................................... 27
4.1 Outcomes of 5S ...................................................................................................... 27 4.2 Data analysis .......................................................................................................... 28
4.2.1 Safety Climate Assessment Toolkit ................................................................ 28 4.2.2 Productivity measures ................................................................................... 31
5 DISCUSSION ......................................................................................................... 33
5.1 Limitations............................................................................................................. 38 5.2 Future research ...................................................................................................... 38
5.3 Conclusion ............................................................................................................. 39
v
REFERENCES .............................................................................................................. 40
APPENDIX 1: SAFETY CLIMATE ASSESSMENT TOOLKIT ................................... 44
APPENDIX 2: INFORMED CONSENT FORM ........................................................... 47
APPENDIX 3: IRB APPROVAL FORM ....................................................................... 49
VITA ............................................................................................................................. 50
vi
LIST OF TABLES
Table 1: Seven wastes in manufacturing from TPS ............................................................ 6
Table 2: Safety Climate Survey Scale .............................................................................. 18
Table 3: Different components of SCAT ......................................................................... 19
Table 4: Safety climate questionnaire mean, standard deviation and t-test results of the case group ............................................................................................................................. 29
Table 5: Safety climate questionnaire mean, standard deviation and t-test results of the
control group .................................................................................................................. 30
Table 6: Possible impact on safety due to changes made in the different phases of 5S ........ 34
vii
LIST OF FIGURES
Figure 1: Non-fatal occupational injuries & illnesses – trend for private industries .............. 2
Figure 2: Understanding the impact of lean on safety climate of assembly workers ............. 4
Figure 3: House of lean ..................................................................................................... 8
Figure 4: Change in mean total safety climate scores of the case and the control groups due to 5S .............................................................................................................................. 30
viii
ABSTRACT
The occupational injury rate in the manufacturing sector is higher than the average
of all private industries, necessitating safety studies. Occupational safety can be measured
through different approaches. Safety climate, a predictive measure of safety, studies the
workers’ perceptions of safety of the workplace. This measure includes several dimensions
of safety like management commitment, involvement and work place hazard evaluation and
was chosen as a method of evaluation in this study.
Even though occupational safety is an important concern, management often
prioritizes reducing waste and cost. So, there is a necessity for some technique which
reduces waste and simultaneously improves safety. Lean has been effective in reducing
waste and costs. Researchers have shown that lean might improve occupational safety too.
Nevertheless, empirical evidence to prove the relationship between the two is insufficient. In
this study, 5S, a lean technique, was implemented in a manufacturing company and its
impact on safety climate of the workers was studied to show the relationship between lean
and safety climate of the workers.
Case and control groups took the Safety Climate Assessment Toolkit, a safety
climate questionnaire, both before and after the 5S event. The effectiveness of the 5S event
was determined through three productivity measures (cycle time, floor space utilized, ratio
between inventory and units produced). Statistical analysis showed that the safety climate of
the manufacturing workers increased after the 5S event (p value = 0.0085). The 5S event
was also shown to be effective. The cycle time was reduced by 16.6% and floor space
utilization decreased by 22.2%. 5S not only improved the processes by reducing waste and
costs, but also improved the safety climate of workers.
1
1 INTRODUCTION
1.1 Motivation
Occupational safety is a critical issue. In 2011, an estimated 39 million workers had a
nonfatal occupational injury or illness in the US (Bureau of Labor Statistics). Compensation
cost to employers due to injured workers was $73.9 billion in 2009 (National Academy of
Social Insurance, 2011). In 2006, OSHA reported that lost productivity from workplace
injuries and illness had cost companies $60 billion. Manufacturing accounted for nearly 20%
of all musculoskeletal injuries (Bureau of Labor Statistics).
The safety of employees in manufacturing is adverse. According to the Bureau of
Labor Statistics, in 2011, manufacturing industries had a non-fatal occupational injury rate
of 4.4 per 100 employees, compared to 3.9 in construction and 3.8 overall (Figure 1). In
2010, the specialized manufacturing sector in this study, the fabricated metal product
manufacturing sector, had an incidence rate of 5.6 per 100 (Bureau of Labor Statistics).
Even though the rate is better compared to other adverse industries like nursing, which had
a rate of 7.8 cases per 100 employees (Bureau of Labor Statistics), this rate is considered
high.
There are two different approaches to safety, reactive and proactive. Usual safety measures
like safety incidents, workplace injuries, and absenteeism due to injuries are reactive
measures of safety. They determine the safety of the workplace after the incident. Proactive
measures of safety, such as workplace hazards and safety risk factors, predict the safety of a
workplace. Safety climate also includes management commitment to safety, workplace
2
risks, and employee involvement in safe practices. This results in integrating various
dimensions of the workplace and the people in measuring safety, thereby making safety
climate a reasonable safety measurement. This study utilizes safety climate as a safety
measure.
Figure 1: Non-fatal occupational injuries & illnesses – trend for private industries
1.2 Improving manufacturing challenges and safety through lean
Manufacturers address different challenges like rising manufacturing costs,
inefficiencies, and lack of quality and safety by implementing process improvement
techniques. Lean is a well-established set of principles which aim at reducing waste. It is
used prominently due to its effectiveness and simplicity. Lean works in manufacturing by
decreasing lead time, reducing inventory and reducing waste (Melton, 2005). However,
there is a dire need to improve worker safety. Lean, in theory, is supposed to improve the
working conditions of the employees and eliminate the hazards in the workplace as well
(Ohno, 1978). There are even a few instances where researchers have shown improvements
3
4
5
6
7
8
9
2003 2004 2005 2006 2007 2008 2009 2010 2011
Ca
ses
per
100 e
mp
loyees
Fabricated Metal Product Manufacturing Manufacturing
Construction Average of all Private industries
3
in occupational safety through lean, but they are limited (Rahman, Khamis, Zain, Deros, &
Mahmood, 2010). Primarily due to other critical issues in a manufacturing company like on
time delivery, quality and customer satisfaction, occupational safety is lost in the lean
process. Improving sales volume is critical to any manufacturing company and thereby
making it the first goal. So with lean being well established in optimizing manufacturing
processes and potentially improving occupational safety, it is important to further analyze
the effects of lean. Concrete evidence of lean affecting occupational safety is required. Given
the current need in the competitive manufacturing industry to reduce cost and waste, a
whole system overhaul needs to be in place, which affects all aspects of manufacturing
including occupational safety. Standalone safety initiatives are not sufficient due to a couple
of reasons. One, they concentrate on following a set of regulations drawn by federal
organizations which may or may not necessarily improve occupational safety. Another
reason is, with lean, the employee involvement is very high and this gives the employees a
better perception of targeting the problem area safety-wise and attacking them which the
safety initiatives do not provide. So, this relationship between lean and safety, specifically
safety climate, needs to be understood.
1.3 Objective
Ultimately two different research areas in manufacturing, the different techniques to
improve process and safety simultaneously along with proactive measures of safety like
safety climate vs. reactive measures of safety have focused the current research to
understanding the potential impact of lean on safety climate of assembly workers (Figure 2).
4
Figure 2: Understanding the impact of lean on safety climate of assembly workers
The objective of this study is to examine the potential relationship between lean and
safety climate of assembly workers. 5S is the lean technique implemented in this study. The
subject location is the assembly department at a manufacturing facility at Baton Rouge.
1.4 Research scope and limitations
The scope of this thesis included measuring safety climate of the assembly workers,
quality inspectors, supervisors, other manufacturing workers and employees in the assembly
department at the manufacturing facility. Other safety measures were not considered. 5S
was implemented in the assembly department at the manufacturing facility. Other lean tools
were not implemented. Only 3 assembly workers, one quality inspector and one supervisor
were involved in the implementation of the 5S event as a part of the 5S team. The safety
climate of the 5S team was not measured due to bias. The workers, whose safety climate
was measured, did not participate in the actual 5S implementation; however, their
workplace was modified due to 5S. The productivity metrics used to measure the
effectiveness of the 5S event were cycle time, the available floor space and inventory.
The impact of lean on
safety climate of assembly
workers
Techniques to improve process
and safety simultaneously
Proactive measures of safety like safety climate vs. reactive measures of safety
5
2 LITERATURE REVIEW
This research concentrates on determining the effects of lean on safety climate of
assembly workers. This section reviews the literature and current research gaps on lean in
manufacturing, 5S in manufacturing, safety climate in manufacturing, different surveys
measuring safety climate in manufacturing and finally how lean and safety climate in
manufacturing relate to each other.
2.1 Lean manufacturing
Lean was developed by the Japanese automobile industry after World War II, but its
roots can be traced back to the early days of Ford Motor Company. Lean manufacturing as
introduced by Toyota is a management philosophy with a set of tools which aims at
decreasing waste, optimizing workflow, reducing cost and improving quality (de Koning,
Verver, van den Heuvel, Bisgaard, & Does, 2006). Lean techniques also ensure timely
service or delivery. By identifying and eliminating waste, lean focuses on improving value as
perceived by customers. Hines and Taylor (2000) presented the seven wastes which were
originally extracted from the Toyota Production System (TPS) (Table 1).
Over the years, the application of lean has evolved from the original Toyota
Production System principles to a more customer value orientation. Value is defined as the
capability to deliver the product or service a customer wants with minimal time. In this
respect, process steps can be identified as value-added and non-value added. Value-added
are the steps which are critical in delivering a service or a product to a customer whereas
non-value added should be eliminated (Womack & Jones, 2003). This results in placing
customer value and waste reduction at the center of lean (Al-Araidah, Momani,
Khasawneh, & Momani, 2010).
6
Table 1: Seven wastes in manufacturing from TPS
Wastes Description
Overproduction Producing too much or too soon, resulting in poor flow of information
or goods and excess inventory
Inventory Excessive storage and delay of information or products, resulting in
excess inventory and costs, leading to poor customer service
Motion Poor workplace organization, resulting in poor ergonomics, e.g.,
excessive bending or stretching and frequently lost items
Transportation Excessive movement of people, information or goods, resulting in
wasted time and cost
Inappropriate
processing
Going about work processes using the wrong set of tools, procedures or
systems, often when a simpler approach may be more effective
Defects Frequent errors in paperwork or material/product quality problems
resulting in scrap and/or rework
Waiting Long periods of inactivity for people, information or goods, resulting in
poor flow and long lead-times
Lean in manufacturing focuses on improving the throughput of a facility, reducing
the lead time, inventory, defects, rework and process wastes and ultimately improving
financial savings and customer satisfaction (Melton, 2005). Lean has helped streamline
operations and increase value as perceived by customers (Al-Araidah et al., 2010). Recent
research has shown that organizations have attained significant achievements due to
implementing lean practices. Bayo-Moriones, Bello-Pintado, and Merino-Díaz de Cerio
(2010) reported that applying lean techniques in a manufacturing unit resulted in improved
performance in terms of productivity and quality. This presents the potential of improving
quality while simultaneously decreasing cost in manufacturing facilities.
2.2 5S in manufacturing
There are several common tools within lean like 5S and kaizen which are used to
achieve a lean workplace and improve housekeeping practices. Good housekeeping is an
7
essential quality in a workplace that can reduce safety concerns, retain visual order, improve
employee morale, and increase efficiency and effectiveness (Becker, 2001). In Japan,
housekeeping was first introduced as 5S which stands for 5 Japanese words: Seiri (Sort),
Seiton (Set in order), Seiso (Shine), Seiketsu (Standardize) and Shitsuke (Sustain). These
principles emerged in the post-World War II era to eliminate obstacles for efficient
production (Becker, 2001). According to Bayo-Moriones et al. (2010) 5S is a system where
waste is reduced and productivity and quality are optimized through observing an orderly
work area. The first phase sort eliminates unnecessary, broken and expired items from the
work area by “red tagging” and removal. The second phase set in order focuses on providing
efficient storage areas for the remaining items. Items are labeled and put in place where it is
very easy to locate them. Shine, the third phase, is to thoroughly clean the work area. Daily
schedules to clean the area are created to sustain these changes. Once the first three phases
have been implemented, the next phase is to standardize the best practices in the work area.
Standard operating procedures (SOP) are created or enforced if already available. The newly
developed practices are integrated into the SOP and they become the standard way of
performing actions. The final phase, sustain, often considered the most difficult, is to create
habits of maintaining the changes and properly communicating them to the organization.
The 5S technique includes the whole organization for complete involvement and
systematic implementation at all levels and establishes effective quality processes (Ho,
1999). 5S has been implemented in diverse fields due to its simplicity and immediate results.
Instant return on investment and its applicability to a variety of scenarios are the reasons for
5S’s immense popularity (Kilpatrick, 2003).
8
5S is one of the most commonly applied lean techniques in the manufacturing sector.
According to Wilson (2009), 5S along with Kaizen forms the base foundation for lean
implementation in a manufacturing organization (Figure 3).
Figure 3: House of lean
In manufacturing, 5S is viewed at from different angles. Some researchers view 5S as
a philosophy that encourages workers to think differently, while others look at it as an
organization tool (Bayo-Moriones et al., 2010). However, all agree that 5S is one of the best
known methodologies for improving processes (Ho, 1999). 5S is applied in a variety of areas
in a manufacturing facility. Rahman et al. (2010) reported applying 5S in the offices, the
production line, inventory area, final assembly and the surrounding areas as well.
Results from 5S programs are instant and tangible. 5S in an assembly area reduced
the processing time from 278 minutes to 164 minutes in a manufacturing plant (Perera &
Kulasooriya, 2011). In another study, it reduced the total lead time from 2252 minutes to
just 687 minutes (69% reduction) (Perera & Kulasooriya, 2011). Narain, Yadav, and
9
Antony (2004) reported that 5S along with other lean tools achieved several improvements
in a manufacturing facility like production set up time (74%), production space (17% - 45%),
scrap reduction (75%), machine down time (60% - 100%) and delivery against schedule
(21%). Veza, Gjeldum, and Celent (2011) reported that 5S as a part of a lean initiative in an
assembly area of a manufacturing facility was able to improve several metrics like startup
time, shutdown time, changeover time, maintenance time. 5S along with Pareto analysis
identified and solved 80% of the storage space problems in an equipment storage area (Ballé
& Régnier, 2007).
Apart from statistics and values, many other areas were improved due to 5S
implementation. After the implementation of 5S, employee morale was improved, financial
resources increased by selling unused, old or unnecessary equipment, efficient coordination
at all levels in the organization and increased resource utilization (Veza et al., 2011). In
another example, a better relationship with suppliers was created, workers at all levels were
trained and empowered, awareness was created and ultimately brought a cultural change
throughout the organization through 5S (Ferdousi, 2009).
Although sufficient researchers reporting the advantages of implementing 5S in
manufacturing, most previous research does not mention worker safety as a goal or an
outcome of 5S. The current research addresses this gap by looking at a component of worker
safety. According to Kilpatrick (2003), the primary objective of 5S is to maximize the level
of workplace health and safety in conjunction with increased productivity. Rahman et al.
(2010) agreed that 5S improves health and safety standards in the workplace. However in
most cases, safety is often overlooked when implementing lean. Improved employee safety
is usually just an extra benefit of the 5S program and is not the actual reason for
10
implementation. This makes it difficult to analyze the real relationship between worker
safety and 5S implementation. Concentrating on the limitations of the available literature,
this thesis will examine the relationship between lean and safety climate.
2.3 Safety climate
High risk industries such as aviation, construction, and manufacturing pay
considerable attention to assessing safety (Colla, Bracken, Kinney, & Weeks, 2005).
Traditionally, safety measures have been based on reviewing data of employee fatalities and
injuries. These are the reactive measures of safety. However, organizational, managerial and
human factors are involved in causing workplace incidents. So, nowadays industry is
focusing on predictive measures of safety. One specific emphasis is the assessment of safety
climate (Colla et al., 2005). Safety climate is a predictive measure of safety (Clarke, 2006)
compared to conventional safety measures (work related injuries, safety incidents) which are
reactive.
Safety climate is defined in terms of attitudes towards safety by different researchers;
Donald and Canter (1993) defined safety climate as the workers’ attitudes towards safety in
an organization. Safety climate, according to Neal and Griffin (2004), is more clearly
defined as, “perceptions of procedures and practices relating to safety”, which reflect,
“employee perceptions about the value of safety in an organization” (p. 18).
S.J. Cox and Cox (1991) investigated attitudes towards a number of safety-related
objects and activities, including safety software, people and risk. Safety climate is either
related to unconstructive or constructive beliefs of safety or to evaluations of the workplace.
Griffin and Neal (2000) pointed out that safety climate should be understood in terms of the
employees’ perceptions of safety in the work environment while other elements like
11
attitudes towards safety and workplace hazards should be treated as influences on safety
climate.
The term safety culture has often been used interchangeably with safety climate,
although both have a different history and have been studied independently (Clarke, 2006).
While safety culture refers to the overall beliefs existing in an organization, safety climate
has a more passive implication relating to attitudes and perceptions of the members to both
internal and external influences (Glendon, 2005). Mearns, Whitaker, and Flin (2001) stated
that safety climate is a more appropriate term for the output from the questionnaires.
Safety climate is often measured by questionnaires which might include several
dimensions like management commitment, supervisor competence, work pressure, risk
perception and regard for procedures (Mearns et al., 2001). Different surveys measuring
safety climate have been developed for manufacturing (Zohar, 2002), construction (Gillen,
Baltz, Gassel, Kirsch, & Vaccaro, 2002), service (Barling, Loughlin, & Kelloway, 2002),
nuclear (Lee & Harrison, 2000) and telecommunications industries (Hayes, Perander,
Smecko, & Trask, 1998).
2.4 Safety climate in manufacturing
Safety climate is considered the most effective measure for measuring workplace
safety in manufacturing facilities (Baek, Bae, Ham, & Singh, 2008). In manufacturing
industries, researchers argue that given the increase in occupational injuries and accident
rates, the workers’ perceptions of safety of their workplace might be a reason (Oliver,
Cheyne, Tomás, & Cox, 2002). Johnson (2007) explains that the explanatory power of the
conventional methods of measuring safety, i.e. reactive, is incomplete and several other
factors are required to truly understand the safety in a workplace. Employees’ attitudes
12
toward safety, safe practices, management commitment to safety and potential risks are vital
parts to be understood to realize the overall importance of safety in the manufacturing
sector. Measuring safety climate, which includes all these components, is therefore of great
importance.
Safety climate questionnaires were initially developed for measuring the perceptions
of safety of employees. Several researchers identified key dimensions in their surveys like
management commitment, co-worker safety, perceived risk in the workplace, organization
support and so on; however there is no particular safety survey which is considered the most
effective (Gillen et al., 2002; Hayes et al., 1998; Lee & Harrison, 2000; Zohar, 2002).
Particularly pertaining to this study, several questionnaires were rejected due to their
irrelevant models. Certain dimensions like personal risks, safety rules and procedures and
work environment were not available in these surveys (Gillen et al., 2002; Hayes et al.,
1998; Lee & Harrison, 2000; Zohar, 2002). These dimensions are extremely relevant to this
study due to the fact that they may be impacted by implementing 5S.
Therefore, given the prerequisites, the safety climate survey used in this research is
the Safety Climate Assessment Toolkit (SCAT) which was developed by the UK Health and
Safety Executive (HSE) (S. J. Cox & Cheyne, 2000). This was originally developed for oil
extraction companies, but later on became one of the most commonly applied
questionnaires in the manufacturing industries as well (Tomás, Cheyne, & Oliver, 2011).
This questionnaire contains 43 items from 8 dimensions which are; Management
Commitment, Communication, Priority of Safety, Supportive Environment, Involvement,
Personal Priorities and Need for Safety, Personal Appreciation of Risk and Work
Environment.
13
The SCAT uses a 5point Likert type scale with 1 being “strongly disagree” to 5 being
“strongly agree”. This survey was developed from a variety of established safety climate
questionnaires (Donald & Canter, 1993; Lee & Harrison, 2000; Zohar, 2002). This
instrument has shown adequate validity. The survey had a minimum Cronbach’s α value of
0.64 for the different dimensions (S. J. Cox & Cheyne, 2000). Tomás et al. (2011) applied
this survey tool in several industries in Spain and reported a minimum Cronbach’s α score
of 0.78 for the different dimensions. Kao, Stewart, and Lee (2009) implemented the SCAT
along with a few other surveys to measure the safety climate in an airline setting and
reported that the different dimensions were valid with a Cronbach’s α score of 0.89.
Antonsen (2009) compared the SCAT with several other questionnaires and reported that
they measured similar dimensions of safety. Even though the Cronbach’s α scores are less
than 0.8 in most of the applications, according to Nunnally (1978), the range could be 0.75
to 0.83 with at least one dimension claiming a value above 0.90, which the mentioned
applications all had, thus making the SCAT reliable.
The suitability of this survey (SCAT) to this thesis is due to the relationship between
the dimensions of the survey to the lean implementation. Several dimensions of SCAT are
going to be potentially affected by the 5S event. Work Environment, Management
commitment, and communication, for example, will be potentially changed as a part of the
5S event. So, with the confirmed validity of SCAT, it is hypothesized to be effective in
capturing safety dimensions that change as a result of 5S.
2.5 Safety & lean
Concepts of lean like reducing waste, optimizing work flow, and increasing quality
often leads to reducing unwanted motions and resources which may reduce workplace
14
hazards and improve safety (Ikuma, Nahmens, & James, 2011). Several researchers
presented cases where implementing lean has improved safety. Safety personnel in an
automobile industry in Brazil, where lean techniques were applied, reported that the most
significant improvement was in the employees’ perceptions of safety (Saurin & Ferreira,
2009). In manufacturing, Brown and O’Rourke (2007) presented that the best way to
promote worker safety is through lean production by training the workers with the
knowledge, skills and presence of mind to identify and eliminate hazards in the workplace.
They reported that several hazards like noise, heat, ergonomic, machine guarding and
radiation exposure were deeply reduced due to lean operations. However, no empirical
results were presented by Brown and O’Rourke (2007). Jamian, Rahman, Ismail, and Ismail
(2012) similarly reported that 5S generated benefits for the workers in terms of safety, health
and discipline in addition to optimizing the on time delivery and reducing cost in a midsize
manufacturing company. No quantifiable results on worker safety were reported by Jamian
et al. (2012) either. The available literature showcasing the potential benefits of lean on
worker safety are insufficient as empirical results in terms of worker safety were not
reported. These results are required to quantify safety improvements. This ultimately fails in
substantiating the real relationship between lean and worker safety.
Summarizing the available literature, lean is potentially an efficient tool to improve
the work flow and safety and to reduce waste in manufacturing. Given the need to improve
sales and reduce cost in manufacturing, lean is the most commonly applied tool. 5S, an
important tool of lean, concentrates on improving the layout of the workplace and reducing
cost and waste. Moreover, 5S is simple, effective, easy to implement, and produces quick
results. This makes 5S favorable over other lean tools which may take longer to realize
15
benefits. However, occupational safety needs to be stressed. With lean already being
implemented to optimize processes, its impact on improving occupational safety needs to be
verified. Predictive measures of occupational safety are critical here as lean has a potential
chance of affecting them. Lean initiatives or implementations directly affect the employees
perceptions of the workplace and thereby safety too. So, this bridge which connects lean and
the employee’s perceptions of safety needs to be explored. This has ultimately directed the
scope of this research to one particular question: What is the impact of the implementation
of 5S on the safety climate of manufacturing workers?
16
3 METHODS
3.1 Purpose of research
The purpose of this research was to explore the effects of 5S on safety climate of
assembly workers in a manufacturing facility. This research was performed in the assembly
area at the manufacturing facility in Baton Rouge, LA. A 5S event was implemented and
safety climate and productivity of the workers were measured before and after the 5S event.
Safety climate was compared with a control group at the same company that did not
undertake any lean events during the same time period.
3.2 Research question and hypotheses
The research question in this study was: Did the 5S event influence the safety climate of the
assembly workers?
The question analyzed the impact of 5S on the safety climate of the assembly
workers. This study used the safety climate survey Safety Climate Assessment Tool (SCAT)
to understand the changes in employees’ perceptions of safety before and after the
implementation of the 5S event.
Hypotheses were defined at the beginning of the study to confine the statistical
analysis to the specific research questions.
a. Ha – Case vs. control group
Null Hypothesis, Ha0: There is no significant difference in the initial total safety
climate between the case and the control groups.
Alternate Hypothesis, Ha1: There is a significant difference in the initial total
safety climate between the case and the control groups.
17
b. Hb – Safety climate & its components
Null Hypothesis, Hb0: There is no significant impact on the total safety climate
and its different components after the 5S event.
Alternate Hypothesis, Hb1: There is a significant impact on the total safety
climate and its different components after the 5S event.
c. Hc – Cycle time
Null Hypothesis, Hc0: There is no significant change in the cycle time after the 5S
event.
Alternate Hypothesis, Hc1: There is a significant change in the cycle time after the
5S event.
d. Hd – Floor area
Null Hypothesis, Hd0: There are no changes in the floor area after the 5S event.
Alternate Hypothesis, Hd1: There are changes in the floor area after the 5S event.
e. He – Inventory held up
Null Hypothesis, He0: There are no significant changes in the inventory after the
5S event.
Alternate Hypothesis, He1: There are significant changes in the inventory after
the 5S event.
18
3.3 Participants
Around 15 employees worked in or around the assembly area. These workers were
directly affected by the 5S. They included assembly workers, quality inspectors, and
supervisors. These employees formed the case group of this study. The participants in the 5S
implementation were three assembly workers, one quality inspector, one supervisor, one
lean organizer and the researcher. The rest of the participants (~10) took part in the survey
as they were affected by the 5S.
The control group was used to determine if the potential changes in the safety
climate are due to the 5S event or some other confounding factor. Employees from different
departments (welding, scales, machining, inventory and shipping) in the shop floor formed
the control group by taking the safety climate questionnaire at the same time as the case
group.
3.4 Safety climate survey
The safety climate survey (Appendix 1) used in this study was the Safety Climate
Assessment Tool (SCAT) developed by S. J. Cox and Cheyne (2000). The SCAT measured
the perceptions of safety on a Likert – type 5 point scale (Table 2).
Table 2: Safety Climate Survey Scale
Rating Scale
Strongly Disagree 1
Disagree 2
Neither Agree nor Disagree 3
Agree 4
Strongly Agree 5
19
The SCAT included a total of 43 questions with 8 different components (Table 3).
The final score and the section wise scores was obtained by adding the points as per the
Likert scale. The maximum score that could be obtained was 215 and the minimum score
that could be obtained was 43. Higher scores indicated better safety climate. A meaningful
change in safety climate of the employees could be observed in three to five months (Cooper
& Phillips, 2004). Due to the extensive changes in the work environment and introduction
of standards through 5S, a change in safety climate of employees was potentially observable.
Table 3: Different components of SCAT
Components # of Questions
Management Commitment 7
Communication 5
Priority of Safety 7
Supportive Environment 6
Involvement 3
Personal Priorities and Need for Safety 5
Personal Appreciation of Risk 4
Work Environment 6
3.5 5S productivity measures
The effectiveness of the 5S event was tested using three productivity measures.
i. Cycle time: The cycle time in this study was defined as the time it takes the assembly
worker to assemble a unit with all the parts. In the assembly area at the company, assembly
of each unit was done by one specific worker. The worker obtained the parts required for
assembly and starts the assembly. Once, the worker finished the assembly, the worker
placed it in the crating area and started on the next unit. Sometimes, due to high load, the
assembly worker worked on two or more units and then sent them to shipping at the same
20
time. The cycle time was measured by time study; which involved measuring the
continuous time, using a stop watch (or a phone), for predetermined events. This entire
process was already performed by the manufacturing engineer at the facility as part of the
lean initiatives in the company. The cycle time for each part in the assembly was already
available. These times were used as Pre - 5S Cycle times as they are recent. No changes in
the layout or the standard operating procedures were made after the time study. The cycle
time of the assembly of different parts after 5S was measured. This was done by visual
observation on the assembly workers. Using the available data, the actual number of cycles
to be measured was calculated as;
(
)
(
)
Where,
N = Final number of cycles to be observed
Z = Value from the Z table (Z = 1.96 for 95% confidence interval)
E = Accuracy (±5%) x Average cycle time (35 minutes for the initial five
observations)
s = Standard Deviation of the cycle time (three minutes for the initial five
observations)
This was done one week before and one month after the implementation of the 5S
event.
21
ii. Floor space: A successful 5S event usually frees the available floor space previously
held up by unnecessary items. Increased floor space is one of the visual indicators of a
successful 5S event. The available floor space was measured both before and after the 5S
implementation.
iii. Inventory: Inventory (parts ready to be assembled) in the assembly area, in terms of
dollars, was measured both before and after the 5S implementation. A ratio between the
inventory available in dollars and number of units produced in the particular day was
calculated.
3.6 5S implementation
5S is a lean housekeeping technique to improve visual order that uses five standard
steps. Each of these steps was implemented over a span of two weeks. The 5S was initiated
by the company as a part of the lean strategy. The 5 steps were:
i. Sort: In the first step, all the unnecessary tools, items and parts was eliminated. Only
the essential items were retained. This was be done by red tagging all the unwanted
items and prioritizing the required items based on the necessity. The frequently used
items were made more accessible than the others. The supervisor verified the red
tagged items and discarded them.
ii. Set in order: The step involved assigning places for all the retained items. They were
clearly labeled. Foamed toolkits were utilized to assign a set of tools to every assembly
worker. Colored bands were inserted on the tools to identify the toolbox and the area.
Physical marking on the floor was done with special colored tape. Each worker was
assigned two tables which will be his work cell. This phase made sure that there was a
specific location for each worker, item and equipment.
22
iii. Shine: This step involved cleaning the workplace. An activity task list was established
to make sure that the workplace was regularly maintained. At the end of every shift,
the worker cleaned his work cell. The assembly area floor was cleaned on a turn-by-
turn basis as per the schedules.
iv. Standardize: This step involved standardizing the work practices. Standards were
established so that using the tools, obtaining the parts, cleaning the area and standard
operating procedures were followed. The assembly workers were educated on their
responsibilities.
v. Sustain: The final phase made sure that the changes were sustained. The results of the
5S event were communicated to everyone who had access to the implemented area. A
checklist which was developed by the manufacturing engineer was utilized as a part of
this phase to audit the 5S. It included 50 items with 5 sections and 10 questions in each
section. Each section denoted the different steps in 5S. Each question included a
“findings” section which had a “YES” or a “NO” option. The total number of “NO”
options or non-conformances was the final rating of the 5S event at that instance. A
lower rating meant more effective sustainment of the 5S event. This checklist was filled
out by one of the assembly workers once a week after the 5S implementation. This was
a continuously improving process and so should be maintained forever. A notice board
was put up which included all the changes made, the results of the checklist and area
for future changes made by the assembly worker. Employees were asked to come up
with better suggestions to improve the workplace.
23
3.7 Experimental design
3.7.1 Dependent variables
The dependent variables in this study were the different components of the safety
survey (SCAT in this case) and the productivity measures. The dependent variables were:
i. Safety Climate (total score)
a. Management Commitment
b. Communication
c. Priority of Safety
d. Supportive Environment
e. Involvement
f. Personal Priorities and Need for Safety
g. Personal Appreciation of Risk
h. Work Environment.
The total score of the questionnaire and the scores for each section were considered.
ii. Cycle time (minutes)
iii. Floor space (square feet)
iv. Inventory (inventory held up vs. number of units)
Statistical analysis evaluated the relationship between safety climate and 5S. The
effectiveness of the 5S was tested through these different metrics. This helped determine if
the changes in the safety climate were due to the 5S event.
24
3.7.2 Independent variables
The independent variables in this study were time and case vs. control group
analysis. The dependent variables were measured at two different points in time. The
productivity metrics were measured one week before the 5S and 4 weeks after the 5S in the
assembly area. The safety climate questionnaires were administered to both the case and
control groups before and after the 5S.
3.8 Procedure
The procedure was approved by the Institutional Review Board of the university and
the organization with the informed consent form (Appendix 2).
i. Pre – 5S Safety Climate Surveys was conducted on the participants involved in the
study 1 week before the 5S event. The participant pool did not include any member
from the 5S team. Informed consent forms (Appendix 2) were provided to the
participants explaining the procedure, risks, benefits and the privacy information.
ii. The control group took the safety climate questionnaire at the same time as the case
group.
iii. The cycle time was measured by time studies (Pre – 5S Productivity Measures) one
week before the implementation of the 5S event.
iv. The 5S event was a company initiated event and so all the training and audits were
conducted by the in-house manufacturing engineers. All the resources required for the
5S was predetermined by the manufacturing engineers.
v. The 5S event was implemented which involved the 5 standard steps (3.6 5S
Implementation). The first 4 phases will completed over a period of 4 days. Each of
these steps took 2 to 3 hours. The last phase, sustain would go on forever.
25
vi. The cycle time was measured by time studies (Post – 5S Productivity Measures) 1
month after the implementation of the 5S event.
vii. Post – 5S Safety Climate questionnaire was conducted 1 month after the 5S
implementation on the participants involved in the study and the control group.
viii. Periodic audits of the implemented 5S event with checklists to sustain the changes
implemented were performed with an interval of 1 week. This was done by the
assembly workers.
3.9 Statistical analysis
The data collected from the productivity measures (cycle time, floor, inventory) and
the safety climate questionnaires were statistically analyzed to test the hypotheses.
Independent two sample t - test was performed on the initial total safety climate
scores of the case and the control group at a 0.05 level of significance. If the p – value from
the two sample t – test was less than 0.05, the null hypothesis H0, will be rejected meaning
there was a significant difference in the initial total safety climate scores between the case
and the control groups and so they could not be compared. However, if the null hypothesis
was not rejected, then the initial safety climate scores were statistically not different and
they could be compared. The questionnaires obtained from the control group were used to
find out if the potential changes in the safety climate of the case group are due to the 5S. If
the safety climate of the control group remained unchanged, then the potential changes in
the safety climate of the case group could be assumed to have been developed due to the 5S.
Paired t – tests with a difference in the SCAT scores (total score and individual
section scores) from the pre and the post 5S implementation safety climate questionnaires
26
were performed with a 0.05 level of significance. If the p – value from the paired t – test was
less than 0.05, then the null hypothesis H0 would be rejected meaning there was a significant
impact on the safety climate due to the 5S event. If not, the null hypothesis would be
retained meaning no significant impact on the safety climate of the workers.
The cycle time for assembly were measured before and after the 5S and an
independent t test was performed with a 0.05 level of significance. This helped find out if the
cycle time would decrease significantly after the 5S event.
The area available in the floor in the assembly area before and after the 5S was
compared. As it was just one value, it was compared to see if it reduced after the 5S. If the
area available was reduced, then it was assumed that the 5S event enabled the reduction.
This also helped in determining if the 5S event is effective.
A ratio between the inventory held up and units produced would be calculated.
Lower ratio equaled to better productivity. An independent t test was performed with a 0.05
level of significance on the ratios. This helped find out if the inventory held would decrease
significantly after the 5S event.
Ultimately, these statistical analyses helped answer the research questions as
mentioned in the beginning of the section.
27
4 RESULTS
The present research was carried out in the assembly area in the manufacturing
facility. This section presents the results obtained from the Safety Climate Assessment
Toolkit questionnaires and the different productivity measures.
4.1 Outcomes of 5S
The 5S event was a part of the lean initiative at the manufacturing facility. Several
changes were made to the layout, operating procedures, tool organization, material
handling and cleaning schedules.
The first phase, sort, resulted in removing unwanted items, broken tools and
cabinets, unused parts and scrap materials. Unused inventory was returned to purchasing,
rarely used tools and items were assigned a new location and scrap items were discarded.
The second phase, set in order, resulted in several changes in the organization of the
workplace. Each of the four workstations received their own set of tools in foam cut outs
and new toolkits. All the tools were color coded to their respective workstation. All
equipment had specific locations. Trashcans and other items on the floor had floor markers
to indicate their locations. All tools and hoses were removed from the floor and were placed
on clamps. Commonly used parts were placed in bins on every workstation.
The third phase, shine, resulted in removing scrap, dust and other unwanted items
from each workstation. This initial clean-up helped to visualize other issues clearly.
The fourth phase, standardize, resulted in developing standard operating procedures
for the employees in the assembly area. Some of the standards developed were:
28
1. Each worker should use the tools assigned to him and put back the tools in their
allocated location after use.
2. No units should be placed on the floor.
3. Any time a tool is missing, it should be immediately reported to the supervisor.
4. Once a unit is assembled, it should be moved to a “Ready to be shipped” area.
The fifth phase, sustain, resulted in the assembly employees conducting periodic
audits to monitor the changes made through 5S in the assembly area. Once a week, the
activities needed for continuous improvement and the audit results were put up on an
electronic notice board.
4.2 Data analysis
4.2.1 Safety Climate Assessment Toolkit
Out of 24 participants approached, 18 complete sets of questionnaires (Safety
Climate Assessment Toolkit) were obtained (9 participants from the case group and 9
participants from the control group). Demographics of both groups were collected. Mean
age was 32.3 (8.73) years for the case group and 39.9 (6.62) years for the control group.
Mean experience for the case group was 2.28 (1.48) years and 3.56 (1.76) years for the
control group.
An independent 2-sample t test was performed to determine if the case and control
groups could be compared. Safety climate scores for both groups were similar (p value =
0.708) before 5S and thus were useful in finding out if 5S was the only contributing factor to
any potential increase in the safety climate of the case group. This supports hypothesis 1.
29
Mean and standard deviation of the total score and the scores of the individual
dimensions of the questionnaire of the case group are presented in Table 4. The mean total
score improved from 136 to 153 in the case group. Paired t-test with the pre and post 5S
questionnaires were performed on total scores and scores for eight individual dimensions of
the questionnaire for the case group. The p-values are presented in Table 4.
Table 4: Safety climate questionnaire mean, standard deviation and t-test results of the case group
Dimensions of SCAT Pre 5S Post 5S
p-value Mean (SD) Mean (SD)
Management Commitment 21 (2.3) 25 (2.8) 0.0016
Communication 18 (2.9) 19 (3.0) 0.2897
Priority of Safety 25 (3.0) 28 (3.2) 0.0455
Supportive Environment 19 (3.3) 20 (3.1) 0.1837
Involvement 7 (2.3) 10 (2.3) 0.0102
Personal Priorities and Need for Safety 18 (2.0) 18 (2.6) 0.8805
Personal Appreciation of Risk 12 (3.8) 14 (3.4) 0.0755
Work Environment 16 (4.7) 19 (5.1) 0.0071
Total Score 136 (12) 153 (14) 0.0002
Four individual dimensions’ scores, Management Commitment, Priority of Safety,
Involvement and Work Environment, and the total score had p values less than 0.05 and so
these dimensions of safety climate improved after 5S. This supports hypothesis 2.
Paired t-test with the pre and post 5S questionnaires were performed for the control
group. The mean total score improved from 134 to 136 in the control group. The p-values
are presented in Table 5. The p value of the total score was 0.3003 and so, the null
hypothesis was retained and there was no significant change in the total score after the 5S
event for the control group. Two individual dimensions’ scores, supportive environment
and involvement had p values less that 0.05 and so these dimensions increased significantly.
30
Table 5: Safety climate questionnaire mean, standard deviation and t-test results of the control group
Dimensions of SCAT Pre 5S Post 5S
p-value Mean (SD) Mean (SD)
Management Commitment 22 (2.3) 22 (2) 0.8487
Communication 20 (4) 18 (4.6) 0.2995
Priority of Safety 24 (2.8) 25 (3.6) 0.0960
Supportive Environment 18 (3.3) 20 (3.6) 0.0207
Involvement 6 (2.3) 8 (2.5) 0.0353
Personal Priorities and Need for Safety 17 (2.7) 16 (2.3) 0.5596
Personal Appreciation of Risk 13 (3.2) 13 (2.5) 0.7245
Work Environment 16 (4.2) 14 (1.7) 0.3122
Total Score 134 (9.1) 136 (7.8) 0.3003
Figure 4 shows the increase in the mean total scores for both the groups after 5S. In
conclusion, the total safety climate improved after 5S for the case group, whereas there was
no difference for the control group.
Figure 4: Change in mean total safety climate scores of the case and the control groups due
to 5S
0
20
40
60
80
100
120
140
160
180
Case Group Control Group
Mean
To
tal
Sco
re
Groups
Pre 5S
Post 5S
31
4.2.2 Productivity measures
i. Cycle time
The cycle time was predefined as the time it takes the assembly worker to assemble a
unit with all the parts. Initially, the cycle time to assemble a unit with the following parts
was calculated before the 5S event.
Flange – 2 (8 studs each)
Scale – 1 (150 cm)
Gate Valve – 1
Electronic Comp – 1
QC Electronic Comp – 1
Name tag – 1
This was done by using a video camera, a stop watch and a computer.
All the parts were readily available on the workstation. The average total time to
assemble all these parts was 33 (4.6) minutes, as measured with 12 samples. One month
after the 5S event, the cycle time was again calculated with the same conditions to assemble
the same parts with 12 samples. The total time to assemble was 27.5 (2.94) minutes. An
independent t test showed the cycle time after the 5S decreased significantly (p value =
0.002). This showed that the 5S event effectively reduced the cycle time of assembling a
unit. This supports hypothesis 3.
ii. Floor space utilization
The floor space utilized by assembly for material storage, handling and aisles were
measured both before and after the 5S event. Before the 5S, the area utilized by assembly
was 52.2 m2. The first phase of 5S, sort, resulted in removing unnecessary equipment and
32
parts which took up space in the workplace. The fourth phase, standardize, led to
implementation of a pull concept as opposed to the traditional push concept. This resulted
in moving the units to the next step immediately after completion, which was crating in this
case. So, the units were never placed on the floor, which freed up space. The floor space
utilized by final assembly after 5S was 42.7 m2, which is a 22.2% decrease. This supports
hypothesis 4.
iii. Inventory held up
The inventory held up in the racks allocated for assembly included finished parts
from other departments ready for assembly. This measure was monitored along with units
produced on that particular day. These parameters were observed for 6 days before the 5S
and for 6 days one month after the 5S.
A ratio (inventory held up to the number of units finished) was developed. Lower
ratio equaled to better inventory management. A mean ratio of $ 5.79 per unit (0.62)
($144,866 in inventory held up to 25 units finished) was calculated before the 5S event. One
month after the 5S, the mean ratio was reduced to $ 3.67 per unit (0.43) ($113,833 in
inventory held up to 31 units finished). The ratio decreased by 36.6% after 5S. An
independent t test showed ratio after the 5S decreased significantly (p value = 0.0085). This
showed that the 5S event effectively reduced the inventory held up in the assembly area.
This supports hypothesis 5.
33
5 DISCUSSION
The objective of this study was to study the impact of 5S on the safety climate of
manufacturing workers. The safety climate of the manufacturing workers increased
significantly due to the 5S. The 5S event was also effective in reducing waste, eliminating
costs, and increasing value, as shown by the improvement in the productivity measures.
1. Cycle time was reduced by 16.6% due to the 5S event. Toolkit organization, scrap
and unwanted items removal, efficient material storage and well developed set of
standards attributed to this decrease in the cycle time. This decrease ultimately
reduced the lead time of the whole manufacturing process.
2. Floor space utilization decreased by 22.2% after implementing 5S. Standards were
created which prevented workers from placing units on the floor. Several unused
tools, items and racks were removed. Two workstations were shifted to another
department. These changes decreased the floor space utilized by assembly.
3. Inventory held up was measured as a ratio of inventory available to units produced
to account in for the variability. Kanban concepts, extra bins on the workstations for
common parts, removal of excess parts from racks and ultimately a few racks
themselves helped reduce the inventory by 36.6%. In addition, the number of units
produced increased due to the improvement in the cycle time. This led to a lower
ratio of inventory to units produced.
These improvements due to 5S positively affected the safety climate of the
manufacturing workers. Table 6 shows how the changes made in each phase of the 5S
impacted safety in the work area, which may have led to an increase in the safety climate.
34
Table 6: Possible impact on safety due to changes made in the different phases of 5S
Phase Changes made Possible impact on safety
Sort Unnecessary tools, machines were
removed.
Broken items were removed.
Floor area was cleared.
Risk of using a broken/rusted tool or
machine was eliminated.
No clutter resulted in lower chance of
tripping hazard.
Set in order Every workstation had its own set
of tools in a toolbox.
All tools were color coded and had
a specific location.
Search and travel times were
reduced.
Work environment was more visible and
organized making potential ergonomic
risks and hazards transparent.
Motion waste was reduced resulting in
reduced musculoskeletal disorder risks.
Shine The workstations were cleaned
and maintenance schedules were
created.
No significant impact of this phase on
safety.
Standardize Rules were created to reduce the
cycle time.
Standard operating procedures
were implemented.
Lesser units on the table and floor made
the workplace less prone to slip and trip
hazards.
The workers were no longer prone to
risks of heavier units falling from racks.
Sustain Weekly audits are made to sustain
the changes.
The workers were more involved
in making changes in the
workplace.
The workplace was continuously
monitored for safety hazards.
Solutions to reduce safety hazards were
put forth by different workers rather than
the management alone. This enabled a
thorough impact on reducing hazards
from several perspectives.
Four out of eight dimensions of safety climate were increased. Three of them,
management commitment, priority of safety and involvement were directly affected by the
standards which were setup as a part of the standardize phase. Employees were responsible
for reporting hazards and eliminating them. Employees perceived these changes made by
the management to be positive and safer.
35
The final dimension, work environment, was directly influenced by the physical
changes made to the workplace. Removal of units from the floor, setting standards which
restricted the workers from placing more than one unit on the table at a time, removing
large parts from top shelves, purchasing new tools, utilizing carts instead of moving a unit
by hand and so on helped reduce the safety hazards like falling objects, tripping hazards and
muscle strain. The employees in turn perceived these changes to be safer when compared to
the situation before 5S. This helped increase the score for the “work environment”
dimension of the safety climate questionnaire. Overall, the total safety climate was
significantly increased with positive changes in these four dimensions due to these
improvements.
Communication, supportive environment, personal priorities and need for safety and
personal appreciation of risk are the four other dimensions whose scores increased after the
5S, but not significantly. This could be attributed to the fact that, in theory, these
dimensions are not directly affected 5S. As opposed to the first four dimensions, these four
emphasize on personal and interpersonal safety and not management interaction or work
environment.
Due to bias, the safety climate questionnaires were not administered on the 5S team.
However, personal interviews made with the 5S team on their safety climate provided
valuable insights. The workers reported that as they were personally involved in making
decisions about their workplace, they felt that they were in more control of their
surroundings and thus felt safer. In addition, some of the changes related to removing and
reporting hazards were made by these workers.
36
Scores of two dimensions, supportive environment and involvement increased
significantly for the control group. One reason might be that the administration of the
questionnaires might have increased the perceptions of involvement and supportive work
environment of the workers with respect to safety.
Main, Taubitz, and Wood (2008) reported that lean and safety go along
concurrently. They also reported that any changes through lean in a manufacturing facility
would definitely have an impact on the safety risks, positive or negative. Extreme care
should be taken to make sure that the lean events support occupational safety. The 5S in the
study addressed this concern by making sure that any change made impacted the risks and
hazards positively. This was shown through the increase in the work environment
dimension of the questionnaire.
These results obtained in the study support the available literature. These results
confirm Brown and O’Rourke (2007), who stated that employee engagement through
training and involvement are required to identify and reduce the hazards. This was
specifically observed when two dimensions management commitment and involvement
increased significantly after 5S.
Safety was improved in two key categories; physical work environment and
management involvement. This supports Varonen and Mattila (2000), who reported that
safety level of the work place and the safety practices of the management were driving
factors for the improvement in safety climate.
The 5S event in the assembly area improved the relationship between the supervisors
and the workers through active communication. Every time a tool or equipment was
37
missing, the worker notified the supervisor. If a safety hazard was spotted by the worker, the
supervisor was notified. If a required part was not available, the worker would report it to
the supervisor. The 5S also resulted in creating standard operating procedures which the
workers were trained on. These improvements brought a change in the day to day
operations of the assembly area as predicted by Ferdousi (2009).
The 5S event in the study increased workplace safety along with increased
productivity which coincides with what other researchers proposed. (Kilpatrick, 2003;
Rahman et al., 2010). The 5S event in the study also generated benefits in terms of workers’
health along with reducing costs and wastes. However, the lack of statistical evidence
showcasing the relationship between lean and worker safety, which was the limitation of
Jamian et al. (2012) was considered and overcome by providing quantifiable statistical
analysis to show the impact of 5S on the worker safety.
As presented in the literature section, empirical data to help relate 5S to occupational
safety was potentially insufficient. Moreover, predictive measures of safety were not studied
in relation to lean. This study answered these concerns and provided statistical evidence that
5S increases the safety climate of the manufacturing workers.
Ultimately, the research shows that 5S increases the safety climate of the
manufacturing workers through two results:
i. The total safety climate score and four other dimensions significantly increased while
the total score for the control group did not differ significantly after the 5S event.
ii. All the productivity measures (cycle time, floor area utilized and the inventory held
up) significantly improved due to 5S, thus proving the event to be effective.
38
5.1 Limitations
The results of the study cannot be generalized to the whole manufacturing industry
as the 5S was observed in one area. The facility was a job shop which manufactured highly
customizable, made to order items. 5S might have a different impact on safety climate in
high volume manufacturing industries. Moreover, different areas of a factory like inventory,
testing, machining, etc. might have different results due to lean. The post 5S questionnaires
and measures were obtained one month after the 5S event. Total Safety climate and four of
its dimensions did increase significantly; however, it would be interesting to see what kind
of change would happen to the safety climate over a longer time period (Cooper & Phillips,
2004). A small fraction of the increase in the safety climate of the workers might be
attributed to the bias developed due to the lean training and the anticipation of change due
to lean. Steps were taken to avoid this situation by not including the members of the 5S
team in the participant pool, but there is always a chance of other participants being
influenced.
5.2 Future research
A longitudinal study to understand the changes in safety climate due to lean could be
performed to realize the long term effects due to 5S. Other tools like kaizen, poka yoke
could be implemented to find out if they too have a similar effect of safety climate. Applying
5S in different areas of a factory would be beneficial to understand how other departments’
safety climates are affected. 5S with an overall emphasis on safety in every phase could be
implemented to analyze if the relationship between the two changes significantly.
39
5.3 Conclusion
The 5S implemented in this study successfully improved the safety climate of the
workers. It also improved the cycle time, floor area utilization and inventory held up.
This study ultimately helped in understanding the impact of 5S on the safety climate
of the manufacturing workers in an assembly area. Some dimensions of safety climate
weren’t significantly improved, but overall safety climate improved. It is evident that 5S is
effective in improving the perceptions of safety of the workers.
In conclusion, 5S not only improves the processes by reducing waste and costs, but
also improves the safety climate of workers. This technique may be implemented in other
sectors to realize these benefits.
40
REFERENCES
Al-Araidah, O., Momani, A., Khasawneh, M., & Momani, M. (2010). Lead-time reduction
utilizing lean tools applied to healthcare: The inpatient pharmacy at a local hospital. Journal for Healthcare Quality, 32(1), 59-66. doi: 10.1111/j.1945-1474.2009.00065.x
Antonsen, S. (2009). Safety Culture Assessment: A Mission Impossible? Journal of
Contingencies and Crisis Management, 17(4), 242-254. doi: 10.1111/j.1468-
5973.2009.00585.x
Baek, J.-B., Bae, S., Ham, B.-H., & Singh, K. P. (2008). Safety climate practice in Korean manufacturing industry. Journal of Hazardous Materials, 159(1), 49-52. doi:
10.1016/j.jhazmat.2007.07.125
Ballé, M., & Régnier, A. (2007). Lean as a learning system in a hospital ward. Leadership in
Health Services 20(1), 33-41.
Barling, J., Loughlin, C., & Kelloway, E. K. (2002). Development and test of a model
linking safety-specific transformational leadership and occupational safety. Journal of
Applied Psychology, 87, 488-496.
Bayo-Moriones, Bello-Pintado, & Merino-Díaz de Cerio. (2010). 5S use in manufacturing plants: contextual factors and impact on operating performance. International Journal
of Quality & Reliability Management, 27(2), 217-230.
Becker, J. E. (2001). Implementing 5S to promotes safety & housekeeping. Professional
Safety, 46(8), 29.
Brown, G. D., & O’Rourke, D. (2007). Lean Manufacturing comes to China: A case study
of its impact on Workplace Health and Safety. International Journal of Occupational and
Environmental Health, 13(3), 249 - 257.
Bureau of Labor Statistics. Injuries, Illnesses, and Fatalities, from http://www.bls.gov/iif/
Clarke, S. (2006). Contrasting perceptual, attitudinal and dispositional approaches to accident involvement in the workplace. Safety Science, 44, 537-550.
Colla, J. B., Bracken, A. C., Kinney, L. M., & Weeks, W. B. (2005). Measuring patient
safety climate: a review of surveys. Quality and Safety in Health Care, 14, 364-366.
Cooper, M. D., & Phillips, R. A. (2004). Exploratory analysis of the safety climate and
safety behavior relationship. Journal of Safety Research, 35(5), 497-512. doi:
10.1016/j.jsr.2004.08.004
Cox, S. J., & Cheyne, A. J. T. (2000). Assessing safety culture in offshore environments.
Safety Science, 34(1–3), 111-129. doi: 10.1016/s0925-7535(00)00009-6
41
Cox, S. J., & Cox, T. (1991). The structure of employee attitudes to safety: a European example. Work and Stress, 5, 93–106.
de Koning, H., Verver, J. P. S., van den Heuvel, J., Bisgaard, S., & Does, R. J. M. M.
(2006). Lean six sigma in healthcare. Journal for Healthcare Quality, 28(2), 4-11. doi:
10.1111/j.1945-1474.2006.tb00596.x
Donald, I., & Canter, D. (1993). Psychological factors and the accident plateau. Health and
Safety Information Bulletin, 215, 5-12.
Ferdousi, F. (2009). An investigation of manufacturing performance improvement through lean production: A study on Bangladeshi garment firms. International Journal of
Business and Management, 4(9), 106 - 116.
Gillen, M., Baltz, D., Gassel, M., Kirsch, L., & Vaccaro, D. (2002). Perceived safety
climate, job demands, and coworker support among union and non-union injured construction workers. Journal of Safety Research, 33, 33-51.
Glendon, A. I. (2005). Safety culture. In W. Karwoski (Ed.), International Encyclopedia of
Ergonomics and Human Factors. London: Taylor and Francis.
Griffin, M. A., & Neal, A. (2000). Perceptions of safety at work: A framework for linking
safety climate to safety performance, knowledge, and motivation. Journal of
Occupational Health Psychology, 5(3), 347-358. doi: 10.1037/1076-8998.5.3.347
Hayes, B. E., Perander, J., Smecko, T., & Trask, J. (1998). Measuring perceptions of
workplace safety: development and validation of the Work Safety Scale. Journal of
Safety Research, 29(3), 145-161. doi: 10.1016/s0022-4375(98)00011-5
Hines, P., & Taylor, D. (2000). Going Lean. Cardiff: Lean Enterprise Research Centre.
Ho, S. K. M. (1999). The 5-S auditing. Managerial Auditing Journal, 14(6), 294-302.
Ikuma, L. H., Nahmens, I., & James, J. (2011). Use of safety and lean integrated kaizen to
improve performance in modular homebuilding. Journal of Construction Engineering &
Management, 137(7), 551-560.
Jamian, R., Rahman, M. N. A., Ismail, A. R., & Ismail, N. Z. N. (2012). The use of 5s as
sustainable practices in Manufacturing Small and Medium-sized enterprises. Global
conference on Operations and Supply Chain Management.
Johnson, S. E. (2007). The predictive validity of safety climate. Journal of Safety Research,
38(5), 511-521. doi: 10.1016/j.jsr.2007.07.001
42
Kao, L.-H., Stewart, M., & Lee, K.-H. (2009). Using structural equation modeling to predict cabin safety outcomes among Taiwanese airlines. Transportation Research Part E:
Logistics and Transportation Review, 45(2), 357-365. doi: 10.1016/j.tre.2008.09.007
Kilpatrick, J. (2003). Lean Principles. Manufacturing Extension Partnership. Retrieved from
Lee, T. R., & Harrison, K. (2000). Assessing safety culture in nuclear power stations. Safety
Science, 34, 61-97.
Main, B., Taubitz, M., & Wood, W. (2008). You cannot get lean without safety:
Understanding the common goals. Professional Safety, 53(1).
Mearns, K., Whitaker, S. M., & Flin, R. (2001). Benchmarking safety climate in hazardous
environments: A longitudinal, interorganizational approach. Risk Analysis: An
International Journal, 21(4), 771-786.
Melton, T. (2005). The benefits of lean manufacturing: What lean thinking has to offer the
process industries. Chemical Engineering Research and Design, 83(6), 662-673. doi:
10.1205/cherd.04351
Narain, Yadav, & Antony, J. (2004). Productivity gains from flexible manufacturing:
Experiences from India. International Journal of Productivity and Performance
Management, 53(2), 109 - 128.
National Academy of Social Insurance. (2011). Worker' Compensation 2009. Washington
DC.
Neal, A., & Griffin, M. A. (2004). Safety Climate and Safety at work. In Julian Barling & M. R. Frone (Eds.), The Psychology of Workplace Safety (pp. 15-34). Washington DC:
American Psychological Association.
Nunnally, J. (1978). Psychometric Theory (2nd ed.). New York: McGraw-Hill.
Ohno, T. (1978). Toyota Production System: Beyond Large-Scale Production. Tokyo: Diamond
Inc.
Oliver, A., Cheyne, A., Tomás, J. M., & Cox, S. (2002). The effects of organizational and individual factors on occupational accidents. Journal of Occupational & Organizational
Psychology, 75(4), 473-488.
Perera, C., & Kulasooriya, D. M. A. (2011). Lean Manufacturing: A Case study of a Sri Lankan Manufacturing Organization. South Asian Journal of Management, 18(1), 149 -
158.
Rahman, M. N. A., Khamis, N. K., Zain, R. M., Deros, B. M., & Mahmood, W. H. W.
(2010). Implementation of 5S Practices in the Manufacturing Companies: A Case
43
Study. American Journal of Applied Sciences, 7(8), 1182-1189. doi:
10.3844/ajassp.2010.1182.1189
Saurin, T. A., & Ferreira, C. F. (2009). The impacts of lean production on working
conditions: A case study of a harvester assembly line in Brazil. International Journal of
Industrial Ergonomics, 39(2), 403-412. doi: 10.1016/j.ergon.2008.08.003
Tomás, J. M., Cheyne, A., & Oliver, A. (2011). The relationship between safety attitudes
and occupational accidents: The role of safety climate. European Psychologist, 16(3),
209-219. doi: 10.1027/1016-9040/a000036
Varonen, U., & Mattila, M. (2000). The safety climate and its relationship to safety
practices, safety of the work environment and occupational accidents in eight wood-
processing companies. Accident Analysis & Prevention, 32(6), 761-769. doi:
10.1016/s0001-4575(99)00129-3
Veza, I., Gjeldum, N., & Celent, L. (2011). Lean manufacturing implementation problems
in beverage production systems. International Journal of Industrial Engineering and
Management, 2(1), 21-26.
Wilson, L. (2009). How To Implement Lean Manufacturing: McGraw-Hill Professional.
Womack, J., & Jones, D. (2003). Lean Thinking. Simon & Schuster.
Zohar, D. (2002). The effects of leadership dimensions, safety climate, and assigned
priorities on minor injuries in work groups. Journal of Organizational Behaviour 23, 75-
92.
44
APPENDIX 1: SAFETY CLIMATE ASSESSMENT TOOLKIT
Cover Sheet
(To be filled by Researchers)
Name: ______________________________________
Employee Job title: _____________________________
Participant ID#: ________________________________
45
Safety Climate Assessment Toolkit
Q No.
Question Strongly Disagree
Disagree
Neither Agree
nor Disagree
Agree Strongly Agree
Management Commitment
1 Management acts decisively when a safety concern is raised
2 Management acts only after accidents have occurred
3 Corrective actions are always taken when management is told about unsafe practices
4 In my workplace management acts quickly to correct safety problems
5 In my workplace management turn a blind eye to safety issues
6 In my workplace managers/supervisors show interest in my safety
7 Managers and supervisors express concern if safety procedures are not adhered to
Communication
8 Management operates an open door policy on safety issues
9 My supervisor does not always inform me of current concerns and issues
10 I do not receive praise for working safely
11 Safety information is always brought to my attention by my line manager/supervisor
12 There is good communication here about safety issues which affect me
Priority of Safety
13 I believe that safety issues are not assigned a high priority
14 Management clearly considers the safety of employees of great importance
15 Safety rules and procedures are carefully followed
16 Management considers safety to be equally as important as production Safety Rules and Procedures
17 Sometimes it is necessary to depart from safety requirements for production’s sake
18 Some health and safety rules and procedures are not really practical
19 Some safety rules and procedures do not need to be followed to get the job done safely
46
Q No.
Question Strongly Disagree
Disagree
Neither Agree
nor Disagree
Agree Strongly Agree
Supportive Environment
20 Employees are not encouraged to raise safety concerns
21 Co-workers often give tips to each other on how to work safely
22 I am strongly encouraged to report unsafe conditions
23 When people ignore safety procedures here, I feel it is none of my business
24 A no-blame approach is used to persuade people acting unsafely that their behavior is inappropriate
25 I can influence health and safety performance here
Involvement
26 I am involved in informing management of important safety issues
27 I am never involved in the ongoing review of safety
28 I am involved with safety issues at work
Personal Priorities and Need for Safety
29 Safety is the number one priority in my mind when completing a job
30 Personally I feel that safety issues are not the most important aspect of my
job
31 I understand the safety rules for my job
32 It is important to me that there is a continuing emphasis on safety
33 A safe place to work has a lot of personal meaning to me
Personal Appreciation of Risk
34 I am rarely worried about being injured on the job
35 In my workplace the chances of being involved in an accident are large
36 I am sure it is only a matter of time before I am involved in an accident
37 I am clear about what my responsibilities are for health and safety
Work Environment
38 I cannot always get the equipment I need to do the job safely
39 Operational targets often conflict with safety measures
40 Sometimes conditions here hinder my ability to work safely
41 Sometimes I am not given enough time to get the job done safely
42 There are always enough people available to get the job done safely
43 This is a safer place to work than other companies I have worked for
47
APPENDIX 2: INFORMED CONSENT FORM
Title The impact of 5S on the safety climate of the manufacturing workers
Location Baton Rouge, LA
Participants Assembly workers, Quality Inspectors, Supervisors and workers from other departments
Number of Participants ~ 30
Description A questionnaire (Safety Climate Assessment Toolkit) will be provided which measures your perceptions of safety in the workplace. It has 43 questions with a possible rating of 1 to 5 for each question. This process will take about 15 minutes. The questionnaire has to be taken twice; both before and after 1 month following the 5S event. This questionnaire will be administered to both the control group and the case group. All the information obtained will be kept confidential.
Benefits Participating in this study will contribute to understanding the impact of lean on your perceptions of safety in manufacturing industry.
Subject's Right to Refuse to Participate or Withdraw Participation is voluntary. Refusal to participate will involve no penalty or loss of benefits to which you are otherwise entitled and you may discontinue participation at any time without penalty or loss of benefits to which you are otherwise entitled.
Financial Information You will not be paid for the participation.
Privacy Information Results of the study may be published, but no names or identifying information will be included in the publication. Your identity will remain confidential unless disclosure is required by law. By signing below, you agree to have read and understood the purpose of this questionnaire. ____________________________________ _________________ Signature of Subject Date
____________________________________ Printed Name of Subject
48
____________________________________ _________________ Consent Administered by Date
____________________________________ Printed Name
If you have questions you may contact:
Primary Investigator Laura Hughes Ikuma, Ph. D Assistant Professor, Construction Management & Industrial Engineering Louisiana State University [email protected]
(225) 578-5364
Study Coordinator Siddarth Srinivasan Graduate Student, Construction Management & Industrial Engineering Louisiana State University [email protected] (225) 361-5876
LSU Institutional Review Board (IRB) Dr. Robert Mathews, Chair 131 David Boyd Hall, Baton Rouge, LA Phone: (225) 578-8692
Fax: (225) 578-5983 [email protected]
49
APPENDIX 3: IRB APPROVAL FORM
50
VITA
Siddarth Srinivasan was born in Salem, Tamil Nadu, India. He graduated with a
Bachelor of Engineering degree in Mechanical Engineering from Anna University in May
2010. He joined the Department of Mechanical and Industrial Engineering at Louisiana
State University in August 2010. He plans to graduate with a Master of Science in Industrial
Engineering degree in Fall 2012.
